Deductive and Inductive Reasoning Flashcards

A NYC Department of Buildings regulation states: 'All new construction projects require a preliminary plan review before a permit can be issued.' A contractor submits an application for a permit for a new building but does not include a preliminary plan. Based on this regulation, which of the following conclusions is most logical?

Answer: The contractor's permit application will not be issued until a preliminary plan is reviewed.

This is an example of deductive reasoning. The regulation is a general rule (premise). The contractor's application is a specific case that does not meet the rule's condition. Therefore, the logical conclusion is that the consequence of not meeting the condition—no permit being issued—will apply.

An analyst for the Department of Transportation notices that on the last ten holidays, traffic on the Brooklyn Bridge increased by an average of 30%. The analyst predicts that traffic on the bridge will increase by approximately 30% on the upcoming Labor Day holiday. What type of reasoning is the analyst using?

Answer: Inductive Reasoning

The analyst is using specific past observations (data from ten holidays) to make a general prediction about a future event. This is the definition of inductive reasoning, which moves from specific instances to a broader generalization or prediction. The conclusion is probable, not guaranteed.

Which of the following statements provides the most accurate definition of deductive reasoning?

Answer: It is a logical process that starts from a general, accepted premise and applies it to a specific case to reach a certain conclusion.

Deductive reasoning is a 'top-down' approach. It works by taking a general rule or principle that is known to be true and using it to deduce a conclusion about a specific instance. If the initial premises are true, the conclusion must also be true.

A parks department employee observes that in a specific park, the grass in sections A, B, and C is yellowing. The employee also notes that the sprinkler heads in these three sections appear to be clogged. The sprinkler heads in the rest of the park, where the grass is green, are clear. Which of the following is the most reasonable *inductive* conclusion?

Answer: The yellowing grass is likely being caused by a lack of water due to clogged sprinklers.

Inductive reasoning involves forming a general explanation based on specific observations. The specific observations are the correlation between clogged sprinklers and yellowing grass in certain sections. The most logical generalization is that there is a causal link between the two, providing a probable explanation for the phenomenon.

Consider this argument: 'The employee handbook states that all staff must receive supervisor approval for overtime. Joan is a staff member who worked overtime. Therefore, Joan must have received supervisor approval.' This argument is an example of:

Answer: A deductive conclusion

The argument applies a general rule ('all staff must receive approval') to a specific case ('Joan worked overtime') to arrive at a logically necessary conclusion. This structure, moving from a general principle to a specific, certain outcome, is the hallmark of deductive reasoning.

Review the following premises: 1. To be promoted to Sergeant, a police officer must pass the Sergeant's exam. 2. Officer Chen has not passed the Sergeant's exam. What is the only valid deductive conclusion that can be drawn?

Answer: Officer Chen cannot be promoted to Sergeant.

This is a form of deductive reasoning. Premise 1 establishes a necessary condition for promotion. Premise 2 states that Officer Chen has not met this condition. Therefore, the only conclusion that logically and necessarily follows is that Officer Chen cannot receive the promotion.